Can someone explain gearing numbers?
Robd263
Posts: 52
Sorry for what I am sure is a basic question but can someone give me a layman explanation of the numbers seen on cassettes e.g. 1028, 1232 etc.
I assume certain numbers men lower gears, and easier to climb etc.
What should I be looking for in a bike I want mainly for weekend riding distance and sportive? No plans to race.
Thanks
Rob
I assume certain numbers men lower gears, and easier to climb etc.
What should I be looking for in a bike I want mainly for weekend riding distance and sportive? No plans to race.
Thanks
Rob
0
Comments

The numbers refer to the maximum and minimum number of teeth. So, if you have a 10speed cassette (10 sprockets) and it is a 1223 then the smallest sprocket has 12 teeth and the largest has 23 teeth.         
On Strava.{/url}0 
On the rear, more sprocket teeth means easier climbing. You would see gears like 1123, 1228 or 1134 quoted, which is the range of sprocket sizes on the cassette.
On the front fewer chainring teeth mean easier climbing. Typical choices would be 53/39, 50/34, 50/40/30 or 44/32/22, according to road or MTB and double or triple.
If you are using a 44t chainring and an 11t rear sprocket, the wheel goes round four times for each turn of the pedals.
For 50t and 25t, it's twice, for 30t and 30t, it's once, and for 22t and 32t it's just over 2/3 of a wheel revolution for each turn of the pedals.
With low gears (eg 1:1) climbing is easier as you don't have to lift youself so far up the hill with each turn of the pedals.
With high gears (eg 53t &11t = 4.8:1) because you go further with each turn of the pedals, you can go faster before you can't pedal fast enough any more.
How far you go with a turn of the pedals is also affected by the wheel size  with a bigger wheel you go further.
Gears are often quoted as (eg) 53 x 14 for the chainring and sprocket sizes. This is normal when it's obvious what the wheel size would be, eg in a discussion about road bikes.
They are also often quoted as gear inches (in English). These take the wheel size into account, and are calculated as chainring size / sprocket size multiplied by wheel diameter in inches. E.g. 53/14 x 27" = 102" or 22/32 x 26" = 18".
Continental folk will do a similar thing using the wheel circumference in metres, and call the result "development". E.g. 53/14 x 2.11m = 7.99m. Wheel circumference is often readily available as the cycle computer calibration number.
For noncompetitive sportive riding, I'd recommend a gear range of 30100 inches, though many macho types will say you don't need to go as low as 30, and if you find it hard you should man up and go out and train more.
That would be something like 50/34 (compact double) and 1132 cassette (with MTB rear mech) for double, or 48/38/28 to 1227 for triple.
Triple are more fiddly to set up the changing for, and will never be quite as slick, but you can change to lower gears easily, whilst with compact double you are already pretty much as low as you can go.
Lower gears are likely to be desired if you start carrying touring luggage, if you get faced with something properly steep when you are already tired (eg Kirkstone pass 200 miles into the event), or if you go off to the Alps.0 
^^that pretty much says it all. Good post.0

+1 good post Andrew
if you run a 34/50 compact then a 1128 or even 1230 cassette gives a good range for general recreational riding. 1227 gives smaller gaps but the lowest gear isn't quite as low, so it will depend on how strong you are, how steep the hills are and how you like to ride those hills.Facts are meaningless, you can use facts to prove anything that's remotely true!  Homer0 
Thanks for all the advice. That makes things clearer to me now although I will admit I did get lost in the sums converting things to inches.
So in short are we saying that for sportive riding a 1128 or above (higher numbers) would be suitable and the higher the second number the easier climbing would be?
I consider myself a fairly strong rider and I'm relatively fit but hills are the one area I can struggle with when they are long and I would like them to be a bit easier.0 
Robd263 wrote:So in short are we saying that for sportive riding a 1128 or above (higher numbers) would be suitable and the higher the second number the easier climbing would be?
Correct0 
So the bike I'm currently looking at (which seems to change twice a day too much choice) has 50/34 and 1128. This seems suitable for what I want the bike for based on my understanding of the above.
Am I correct?0 
Yes that's fine, 1230 would be even easier if it is very hilly by you but 28 is fine. I have 50/34 and 1230 but rarely use 30 or the next cog down. Some bikes even have 1132 which is approaching mountain bike gearing and would get you up anything.0